Editor’s note: This post, originally published in June 2018, was the third post in Trudeau’s series on how to engage patients through written materials. In February, he wrote about three pillars to creating health-literate material: purpose, audience, and input. In March, he offered two tips for writing engaging content: use question-style headings and explain technical terms you cannot avoid using. At the time, he pointed out, “Of course, there are many more things to consider. One area that doesn’t get enough attention is how to explain numbers so that patients can understand them.”
About health numeracy
This skill is called health numeracy, and we are not very good at it. Only 9% of U.S. adults have proficient numeracy skills, compared with 12% who have proficient literacy skills. Both could be better, but there’s no denying that numbers confuse most people. Even the definition of health numeracy is difficult. For example, the Department of Health & Human Services defines health numeracy as “[t]he degree to which individuals have the capacity to access, process, interpret, communicate and act on numerical, quantitative, graphical, biostatistical, and probabilistic health information needed to make effective health decisions.” Bio-what?
But the real problem isn’t the definition – it is how often patients are required to interpret numerical information in healthcare. Think about how numbers play a role in:
- Checking temperature
- Dosing medication
- Interpreting nutrition labels
- Determining co-payments, deductibles and insurance premiums
- Checking blood pressure
- Interpreting the risks of a certain treatment option
The list could go on and on. But it is this last one that really concerns me as a health lawyer. How can a patient be truly informed and engaged in their own care if they cannot understand the numbers used to show risk? In fact, there is evidence to show that even healthcare professionals have trouble understanding risk. Yet we ask patients to do this all the time!
Tips to help patients understand numbers
Fortunately, there are a lot of things we can do to help patients better understand what the numbers mean for them. The FDA has a very useful guide that discusses a number of evidence-based best practices for doing so. Here are my five favorites:
- Try to simplify the numerical concept.For example, recommend a 200-pound person lose 10 pounds instead of saying, “lose 5% of your body weight.”
- Use the frequency of something happening – not percentages or other statistics.For example, use “5 out of 100 people” instead of 5% or .05.
- Use visuals to help explain the numbers. But be careful with visuals – they need to be easy to interpret. Don’t include so much information that people get overwhelmed with lines, points and bars. I like to use icon arrays to help emphasize the frequency of something happening. (What’s an icon array? See the graphic to the right.)
- Keep denominators the same to ease comparisons. For example, don’t use “there’s a 1-in-5 chance of event X happening, and there’s a 1-in-10 chance of event Y happening.” Which one is the larger risk? (It’s 1 in 5.) But there is no question about what is worse if you say a 2-in-10 chance v. a 1-in-10 chance.
- Do the math in the document itself. Don’t increase the cognitive burden on patients. Use an example of how to calculate a 20% co-payment on a $1,000 bill instead of just leaving the patients to figure it out on their own.
In the end, creating documents that are understandable and engaging is hard work. There are many things to think about; don’t overlook how you use numbers. And no matter what tips you follow, be sure to confirm with patients (using teachback) that they understand what the numbers mean for their specific situation. Numbers are tricky. We know the majority of people struggle with them, so it’s worth the extra effort.